[FFmpeg-user] -preset veryfast produces smallest file, weird

[Ulf Zibis]

Am 15.10.23 um 17:51 schrieb Reindl Harald:
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> Am 15.10.23 um 17:20 schrieb Ulf Zibis:
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>> With "veryfast" I stated to "not care about *space*", but with "-crf 23" I always stated "care about same quality".
>
> you statet "i don't care about anything but speed"
> you didn't state more or less
Correct, but more speed requires to accept more space for the same video quality, in counterpart to
"for constant quality encoding, you will simply save bitrate by choosing a slower preset".
..... which means "don't care about space".

> is it really that hard to understand that depending on the input results differ *dramatically*? when you have a video with nearly no motion compression works far better

No problem to understand in case of different input, but in my case the input was identical the same for the 3 outputs, so I expect to "save bitrate by choosing a slower preset". This wasn't the case with the exactly identical input. I oppositely had more bitrate with a slower preset.

> it all depends on the input and what quality loss is acceptable
The quality loss was precisely stated by "-crf 23" for all 3 runs.

> and "verfyfast" simply don't care much about details ...
... even if stating the level of details constantly by i.e. "-crf 23" ???

> break the same down to zip: use it for a video or a html-file
> guess what is more compressable

I guess we better would compare zip with i.e. xz. For the same quality (here lossless) zip compresses faster than xz, but needs more space than xz.

-Ulf